I am in the process of replacing my rear main seal on my 80 300 SD. I have dropped the upper oil pan and checked the lower half of the seal and it doesn't look too bad. I was reading old threads on thei topic and I came across some discussion on the two ball berarings that are stuffed in the back of the engine block plugging oil galleries. How do you remove those if they are leaking? Is there any way to replace them? I really don't want to put everything back together only to have to take it all apart again when it still leaks. Any info you might have is greatly appreaciated.

Thanks